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NMR and dielectric studies of hydrated collagen and elastin: Evidence for a delocalized secondary relaxation
- Publication Year :
- 2010
-
Abstract
- Using a combination of dielectric spectroscopy and solid-state deuteron NMR, the hydration water dynamics of connective tissue proteins is studied at sub-ambient temperatures. In this range, the water dynamics follows an Arrhenius law. A scaling analysis of dielectric losses, 'two-phase' NMR spectra, and spin-lattice relaxation times consistently yield evidence for a Gaussian distribution of energy barriers. With the dielectric data as input, random-walk simulations of a large-angle, quasi-isotropic water reorientation provide an approximate description of stimulated-echo data on hydrated elastin. This secondary process takes place in an essentially rigid energy landscape, but in contrast to typical {\beta}-relaxations it is quasi-isotropic and delocalized. The delocalization is inferred from previous NMR diffusometry experiments. To emphasize the distinction from conventional {\beta}-processes, for aqueous systems such a matrix-decoupled relaxation was termed a {\nu}-process. It is emphasized that the phenomenology of this time-honored, 'new' process is shared by many non-aqueous binary glasses in which the constituent components exhibit a sufficient dynamical contrast.
- Subjects :
- Condensed Matter - Soft Condensed Matter
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.1004.4119
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1016/j.jnoncrysol.2010.07.035